Seatbelts have been a common means of preventing serious injury in automobile accidents by restraining occupants in their seats since their first introduction in the late 1950s and early 1960s. More recently advances in seatbelt pretensioning systems have created a number of problems in releasing the seatbelt once an accident has occurred and the pretensioning system has been deployed.
Seatbelt pretensioners have been installed in vehicles for many years and are one of the methods used to enhance the occupant restraint system performance. Although the first systems were installed in vehicles in the late 1970s, pretensioners for seatbelts did not become popular across all makes and models until the late 1990s. Pretensioners are designed to remove any slack in the seatbelt shoulder harness assembly substantially simultaneously with the moment of a collision. The pretensioners will typically be provided on three-point seatbelts for both front-seat occupants and can be placed on the outboard rear-seats, or all three rear-seat positions. For the pretensioner to be effective the seatbelt must be a three-point harness system, not merely a lap belt design.
The more aggressive pretensioner systems will pull the occupant back into their seat simultaneously as it deploys. By maintaining the occupant securely in his/her seat and within the seatbelt restraint system, the occupant will experience a smoother deceleration. Also, the front and side airbags can deploy more effectively with less chance of causing injury to the seated and restrained occupant.
Pretensioners can be located at the buckle or anchor end of a seatbelt shoulder harness assembly and work by lowering the seatbelt buckle downward toward the vehicle floor during the collision. This type of unit may be completely concealed within the seat structure or may be visible along the outboard edge of the seat frame. Alternatively, pretensioners can also be commonly found attached directly to the retractor or take-up spool end of the seatbelt system located in the vehicle doorpost or sidewall. This design essentially spins the take-up spool backward during the crash, pulling excess slack out of the seatbelt and shoulder harness assembly. It is also possible for two pretensioners to be provided on each seatbelt, one located at each end of the seatbelt system.
There are mechanically activated pretensioner designs that do not use electricity to activate, although these are not common. There are also pretensioners that are fired by an electrical signal during a crash, but work completely mechanically by releasing a pre-stressed spring. The large majority of seatbelt pretensioners that are in use today are connected to the airbag wiring circuit. When activated, the pretensioners fire off a small pyrotechnic charge of nitro-cellulose that burns rapidly in a small, enclosed chamber. This mini-explosion causes either a plug to move up a tube as it pulls the seatbelt buckle downward, or a sprocket to spin the seatbelt retractor backward. Both actions cause the seatbelt to retract, removing any slack in the seatbelt restraint system. The newest pretensioner systems combine an electrical pre-tensioning mechanism as well as a pyrotechnic charge. These “smart” systems use information from on-board components such as the vehicle's forward-looking radar, inertia sensors, braking systems or speed monitors to provide full deployment in the event of a crash or an adjustable, partial pretensioning grip that is released if no collision event occurs, e.g., after a sensed hard braking.
There are no visible identifiers for seatbelt pretensioners. It is fair to assume they are in use on at least all front-seat three-point seatbelt systems. Outboard, rear three-point harness systems may also have pretensioners. An accordion-type sleeve, directly below the buckle end of a seatbelt, is a very good indicator that a pretensioner is present at the lower end of the buckle. If deployed during a collision, the seatbelt buckle may be at or even below the top of the seat cushion making access to the seatbelt release button difficult or not possible if the release mechanism is drawn downward into or next to the seat such that it becomes unreachable by the occupant. The accordion sleeve will most likely appear compressed if the pretensioner system has fired.
In the normal course of the day, a seatbelt is easily removed by pressing the seatbelt release button beside the latch mechanism to release the belt so that it can retract normally. If the latch's mechanism has been damaged or destroyed, or the belt is so taut that the latch mechanism will not function properly, or if the release can't be reached based on the car's condition or the position of the occupant as a result of an accident, the occupant may be may be hanging upside down or laying sideways, then that same seatbelt that initially prevented the occupant from being horrifically injured or killed might become an extreme liability to the wellbeing of the occupant. If the seatbelt is unable to be released, or fails to release, or the occupant cannot reach the seatbelt release, the failure of the seatbelt to properly release keeps the occupant restrained in the vehicle that may be at risk of fire, flooding, or being struck by other motor vehicles.
In the event that the latch for the seatbelt system fails to release or the release mechanism is unreachable or positioned where it is inaccessible by the occupant the only remedy is to cut through the seatbelt webbing. This will require a seatbelt system escape tool to provide a means for cutting through the seatbelt. Any good car escape tool will have an easily accessible razor blade that is safely recessed into its handle and positioned at an angle to easily slice through a seatbelt.
However, the problem arises in regard to where to position or store the escape tool so that it will be easily retrievable after an accident and/or the seatbelt latch becomes inoperable. Following an accident an escape tool clipped to the visor may have been dislodged and fallen out of the reach of the occupant with the inoperable latch mechanism. Or, the escape tool stored in any of several storage compartments in the vehicle may not be reachable by the restrained occupant to be retrieved and used to cut through the seatbelt. It is, therefore, an object of the present invention to position the seatbelt escape tool directly onto the seatbelt so as to not require retrieval and to be functional at all times.
The second crucial feature of a car escape tool is a glass breaker. The glass breakers used in hand-held tools are essentially hammerheads made from steel that come to a point which can concentrate the force of your swing. Used properly, a glass breaker will shatter a side window of a vehicle. One should not even attempt breaking the windshield, as this glass is treated specifically to avoid shattering. Cutting through the seatbelt webbing and shattering a side window will allow an occupant to exit the vehicle using the window should the door have been rendered inoperable as a result of an accident.
There are a number of combination seatbelt cutters and glass breaking tools available in the market today. But if the seatbelt escape tool is unable to be retrieved to enable the cutting of the seatbelt, the combined glass breaker will also be unable to be retrieved and used as well. It is also an object of the present invention to combine the glass breaker tool with the seatbelt cutter that is to be positioned onto the seatbelt so that the combination escape tool is instantly usable with the occupant not finding it necessary to locate the escape tool in order to be able to use it to escape by cutting the seatbelt.
Other objects will appear hereinafter.